1. Field of the Invention
The present invention relates to land grid array (LGA) connector assemblyies, and particularly to an LGA connector assembly adapted for receiving an LGA central processing unit (CPU) therein and electrically connecting the CPU with a printed circuit board (PCB).
2. Description of the Prior Art
Referring to FIGS. 3 and 4, a conventional LGA connector assembly 9 is adapted for electrically connecting an LGA CPU (not shown) having a multiplicity of metallic contact pads with a PCB (not shown). The LGA connector assembly 9 comprises an insulative base 91 receiving a plurality of electrical contacts 94, and a lever 92 and a metal clip 93 pivotally mounted to two opposite ends of the base 91 respectively.
The lever 92 comprises a pair of locating portions 921, an offset securing portion 922 between the locating portions 921, a medial portion 923 extending perpendicularly from an end of one of the locating portions 921, and a handle portion 924 extending perpendicularly from a free end of the medial portion 923. The clip 93 comprises a lip 931 at a free end thereof, and a pair of mounting portions 932 extending arcuately from an opposite end thereof.
The base 91 is substantially rectangular. The base 91 defines a rectangular cavity 911 in a middle thereof, and has two opposite sidewalls 915. A portion of the base 91 under the cavity 911 defines a plurality of passageways 916, the passageways 916 receiving a corresponding number of the contacts 94 therein. A pair of slots 912 is defined in one end of the base 91. The mounting portions 932 of the metal clip 93 are received in the slots 912 to pivotably mount the clip 93 to the base 91. A trapezoidal recess 913 is defined in an opposite end of the base 91, and a chamber 914 is defined in said opposite end of the base 91 in communication with the recess 913. The locating portions 921 of the lever 92 are pivotably received in the chamber 914, and the securing portion 922 of the lever 92 is received in the recess 913. An ear 917 is formed on one of the sidewalls 915 of the base 91.
In use, the base 91 is mounted to and electrically connected with the PCB. The metal clip 93 and the medial portion 923 of the lever 92 are oriented perpendicular to the base 91, with the securing portion 922 disposed above the locating portions 921. The CPU is mounted in the cavity 911, and the metallic contact pads of the CPU are loosely attached on the corresponding contacts 94 of the base 91. Then the metal clip 93 is rotated down to loosely contact the CPU. The handle portion 924 of the lever 92 is rotated downwardly, thus rotating the medial portion 923 downwardly. When the securing portion 922 reaches the lip 931 of the clip 93, it engages the lip 931 and drives the lip 931 downwardly. When the medial portion 923 reaches a top of the ear 917 of the base 91, the handle portion 924 is rotated further downwardly until the medial portion 923 is engaged under the ear 917. The ear 917 thus holds the medial portion 133 at a horizontal position. In this position, the securing portion 922 of the lever 92 tightly presses on the lip 931, which in turn tightly presses the metallic contact pads of the CPU on the contacts 64. The LGA connector assembly 9 thus electrically connects the CPU with the PCB.
Conversely, when the handle portion 924 of the lever 92 is rotated upwardly from the horizontal position, the medial portion 923 is released from the ear 917 of the base 91. The handle portion 924 is continued to be rotated upwardly, and the securing portion 922 of the lever 92 releases from the lip 931 of the clip 93. When the medial portion 923 has reached the position perpendicular to the base 91, the clip 93 can be rotated up to the perpendicular position, and the CPU can be taken out from the cavity 911 of the base 91.
At present, with the prevailing trend toward miniaturization of computers, the sizes of LGA connector assemblies used in computers are steadily becoming smaller. In contrast, the number of contacts used in LGA connectors is increasing to meet the need for more signal transmission. These considerations bear on the conventional LGA connector assembly 9 as follows. During the rotation of the lever 92 to force the metallic contact pads of the CPU on the contacts 94 of the base 91, the metal clip 93 and the lever 92 exert forces on the base 91. The forces acting on portions of the base 91 near the slots 912 and at the chamber 914 are greater than those acting on other portions of the base 91. Therefore the base 91 is liable to deform and warp. When deformation or warpage occurs, some contacts 94 cannot firmly contact the metallic contact pads of the CPU, which disrupts the electrical connection between the CPU and the PCB.
In addition, during the above-described operations, the medial portion 923 of the lever 92 exerts force upon the ear 917 of the base 91. The ear 917 is relatively thin, and is typically made of insulative material such as plastic. Thus, the ear 917 is liable to be broken when the lever 92 is operated repeatedly over time. When the ear 917 is broken, the lever 92 cannot be retained at the horizontal position. Instead, the lever 92 accidentally rotates up from the horizontal position, leaving the metallic contact pads of the CPU only loosely engaged with the contacts 94. This easily leads to disruption of the electrical connection between the CPU and the PCB.
In view of the above, a new LGA connector assembly that overcomes the above-mentioned disadvantages is desired.
Accordingly, an object of the present invention is to provide a land grid array (LGA) connector assembly for electrically connecting an electronic package such as an LGA central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB), wherein the LGA connector assembly has a base that resists deformation and warpage.
Another object of the present invention is to provide an LGA connector assembly which has a lever and an ear for reliably retaining the lever, the ear being configured to resist breakage even after repeated operation of the lever.
To achieve the above-mentioned objects, an LGA connector assembly in accordance with a preferred embodiment of the present invention comprises an insulative rectangular base receiving a multiplicity of electrical contacts, a metal reinforcement covering the base, a lever and a metal clip. The base defines a cavity in a middle thereof, and a plurality of holes near the cavity. The clip is mounted to one end of the base. The lever comprise a pair of locating portions received in an opposite end of the base, an offset securing portion between the locating portions engaging the clip, and a medial portion extending perpendicularly from an end of one of the locating portion. The reinforcement comprises a top portion, and two opposite sidewalls depending perpendicularly from the top portion. An ear is formed at one of the sidewalls for orienting the medial portion of the lever. Eight projecting members depend perpendicularly from the top portion. Each projecting member is fittingly received in the corresponding hole of the base. Thus, during rotating the lever to tightly attach a CPU in the cavity of the LGA connector assembly or release the CPU from the contacts, the base and the ear are enough hard to withstand forces from the clip and the lever.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: